1. To know what the digestive system is.

2. To know what jobs all the organs do.

3. To understand the importance of a healthy diet.

The parts of the body that deal with food – from the first bite to getting rid of the waste – are known as the DIGESTIVE SYSTEM.

How much food does a human adult need to eat in a year? 500 kilograms!

Swallowing is the start of a journey for your food that takes 24 hours or more and involves travelling up to 9 metres through a dark tube full of powerful chemicals.

The digestive tract is a long tube that starts at the mouth and ends at the anus.

1. Food is chewed in the mouth and swallowed down the throat. 2. It is pushed through the Oesophagus into the stomach.

3. Then the food travels through the small and large intestines to the anus, where any waste is passed out.

The hypothalamus in our brains makes us feel hungry & thirsty. The brain stem controls the movements of the gut and the removal of food waste.

After you have taken bites of your food and chewed, it quickly becomes mushy due to saliva. Saliva is made in glands on the sides of your face which release up to 1.5 litres a day into your mouth!

There are 3 glands on each side of your face. 1. Parotid – in front of your ear. 2. Submandibular – back of your lower jaw. 3. Sublingual – under your tongue

How many times a day does the average person bite and chew? Over 1100 times!

In the digestive tract, the food is digested (broken down) and absorbed into the body.

Food takes a few seconds to travel down the oesophagus. It is pushed into the bag-like stomach, which attacks the food with powerful acids, enzymes and other chemicals.

The stomach walls have many layers – 3 of these are made of muscle fibres. The muscles tighten and contract the stomach to squash, mix and mash the food.

The stomach also attacks the food with powerful chemicals. Its lining produces a strong acid called hydrochloric acid. The lining also makes enzymes and these both break down different parts of your meal.

After a few hours in the stomach, your meal has become a thick, dark, mushy soup. The mixture then heads down to the small intestine.

The small intestine contains many more enzymes that attack food and continue to break it into smaller pieces. These enzymes come from another digestive organ called the pancreas, which is on the left of your body under the stomach.

There are many folds in its lining, made of millions of tiny fingers called villi. Every single one has a system of tiny vessels for blood and nutrients.

How long is your small intestine? About 6 metres!

The last part of the digestive tract is the large intestine. Its job is to take a few more nutrients from the food and remove as much water as the body needs.

Why is faeces (poo) brown? Because of a substance called bilirubin that comes from the breakdown of old red blood cells in the liver.

The liver is part of the digestive system but isn’t in the digestive tract. It has many jobs. One is to make bile, a green fluid that passes to a small storage bag called the gallbladder.

When food enters the small intestine, bile flows in and helps to break up fat in the food.

The pancreas makes digestive juices that flow through a duct into the small intestine. These juices help neutralize the stomach acid so it doesn’t burn the gut.

Liquid waste (urine) comes from the kidneys, which filter unwanted substances from the blood.

The two tubes (ureters) carry urine down to the bladder – a stretchy bag that holds the urine until it is passed out into the toilet.

ALL of the body’s blood is filtered by the kidneys every 10 minutes. This means that your blood is filtered about 150 times a day!

Your bladder can hold about 0.5 litres of urine, although it is stretchy enough to hold twice that amount. However, when there is about 0.2 litres in your bladder you will feel like going to the loo!

What is the heaviest organ inside the human body? The liver! It weighs about kg in a healthy adult.